Biology 11 Enzymes + Digestion

Chemical reaction

A process that changes substances into different substances by breaking and forming chemical bonds.

Reactants

Substances that start a chemical reaction.

Products

Substances formed as a result of a chemical reaction.

Activation energy

The minimum energy required to start a chemical reaction.

Catalyst

A substance that speeds up a reaction without being consumed.

Enzyme

A biological catalyst that lowers activation energy and speeds up reactions in living cells.

Substrate

The molecule that an enzyme acts on.

Active site

The region of an enzyme where the substrate binds.

Enzyme-Substrate Complex

Temporary structure formed when an enzyme binds to its substrate.

Specific Enzyme Inhibitor

A molecule that binds to an enzyme to prevent it from working on its substrate.

Non-Specific Enzyme Inhibitor

Factors like temperature or pH that can denature or reduce enzyme activity.

Denature

When a protein loses its shape and function due to heat, pH, or chemicals; affects secondary, tertiary, and quaternary structures.

Ingestion and digestion

Ingestion is taking in food; digestion is breaking down food into smaller molecules.

Absorption and elimination

Absorption is taking nutrients into the bloodstream; elimination is removing waste from the body.

Mechanical and Chemical digestion

Mechanical = physical breakdown of food (chewing, churning); Chemical = enzymatic breakdown into smaller molecules.

Peristalsis

Wave-like muscle contractions that move food through the digestive tract.

Mouth

Entry point for food; site of mechanical digestion and chemical digestion via saliva.

Teeth

Structures that physically break down food into smaller pieces.

Saliva

Fluid in the mouth containing water and enzymes (like salivary amylase) to start digestion.

Esophagus

Tube connecting mouth to stomach; moves food via peristalsis.

Stomach

Organ that mixes food with gastric juices; site of mechanical and chemical digestion.

Chyme

Partially digested, semi-liquid food in the stomach.

Villus

Finger-like projections in the small intestine that increase surface area for nutrient absorption.

Pancreas

Organ producing digestive enzymes (lipase, trypsin) and bicarbonate to neutralize stomach acid.

Liver

Produces bile to emulsify fats and process nutrients.

Small intestine

Organ where most chemical digestion and nutrient absorption occurs.

Large intestine

Organ that absorbs water and forms feces.

Gallbladder

Stores and releases bile from the liver into the small intestine.

Salivary Amylase

Enzyme in saliva that breaks down starch into sugars (glucose).

Lipase

Enzyme that breaks down lipids into fatty acids and glycerol; produced by pancreas.

Proteases (pepsin and trypsin)

Enzymes that break down proteins into amino acids; pepsin in stomach, trypsin in pancreas.